Glass, in particular solder glass or fusible glass

ABSTRACT

A glass, for example a glass solder, includes the following components in mole percent (mol-%): P 2 O 5  37-50 mol-%, for example 39-48 mol-%; Al 2 O 3  0-14 mol-%, for example 2-12 mol-%; B 2 O 3  2-10 mol-%, for example 4-8 mol-%; Na 2 O 0-30 mol-%, for example 0-20 mol-%; M 2 O 0-20 mol-%, for example 12-20 mol-%, wherein M is, for example, K, Cs or Rb; Li 2 O 0-42 mol-%, for example 0-40 mol-% or 17-40 mol-%; BaO 0-20 mol-%, for example 0-20 mol-% or 5-20 mol-%; and Bi 2 O 3  0-10 mol-%, for example 1-5 mol-% or 2-5 mol-%.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 13/968,044, entitled “GLASS, IN PARTICULAR GLASS SOLDER OR FUSIBLE GLASS”, filed Aug. 15, 2013 which is incorporated herein by reference. U.S. patent application Ser. No. 13/968,044 is a continuation of PCT application No. PCT/EP2012/000703, entitled “GLASS, IN PARTICULAR GLASS SOLDER OR FUSIBLE GLASS”, filed Feb. 17, 2012 which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a glass and by association to a glass composition, in particular a solder glass as well as to a feed-through for a storage device, such as a lithium-ion battery, for example a lithium-ion accumulator.

2. Description of the Related Art

Solder glasses or fusible glasses are glasses which are used to bond metals having a high heat expansion and low melting temperature, for example by means of soldering with a solder glass or sealing by means of a fusible glass.

Glasses which find use as solder glasses are known from a multitude of patent specifications. For example, U.S. Pat. No. 5,262,364 describes a high expansion solder glass comprising 10-25 mol-% Na₂O; 10-25 mol-% K₂O; 5-15 mol-% Al₂O₃; 35-50 mol-% P₂O₅; and 5-15 mol-% PbO and/or BaO. The solder glass disclosed in U.S. Pat. No. 5,262,364 has a heat expansion at in the range of 16×10⁻⁶ per degree Kelvin (K) to 21×10⁻⁶/K. A disadvantage of the solder glass according to U.S. Pat. No. 5,262,364 is that the solder glass contains lead, in other words PbO as well as a relatively high amount of Na₂O.

U.S. Pat. No. 5,965,479 cites a lead-free high expansion solder glass or fusible glass for use in hermetically sealed housing for high frequency applications. The lead-free high expansion solder glass known from U.S. Pat. No. 5,965,479 comprises 10-25 mol-% Na₂O; 10-25 mol-% K₂O; 4-15 mol-% Al₂O₃; 35-50 mol-% P₂O₅; 5-10 mol-% B₂O₃; and a content of M_(x)O which does not exceed 12 mol-%, whereby M_(x) can be calcium (Ca) or magnesium (Mg). Even though these glasses contain little or no lead, they do have very high alkali content.

Phosphate glasses for joining of metal and glass or glass ceramic are described in U.S. Pat. No. 4,455,384. Such phosphate glasses are generally chemically resistant and vacuum tight. Phosphate glasses in other applications, for example optical applications have been described many times, for example in DE 15996854, JP 90188442, as well as JP91218941 A.

Feed-throughs featuring high thermal expansion materials such as aluminum, aluminum alloys, copper and copper alloys and glass materials have become known only in the area of high frequency feed-throughs (HF feed-through). Such HF feed-throughs with glass materials on the basis of aluminum-phosphate glasses are known for example from U.S. Pat. No. 5,262,364 and U.S. Pat. No. 5,965,469 as well as U.S. Pat. No. 6,037,539.

In particular U.S. Pat. No. 6,037,539 describes an HF feed-through wherein a non-ferrous conductor in an aluminum-phosphate glass composition is guided through a housing component comprising aluminum. The HF feed-through known from U.S. Pat. No. 6,037,539 is substantially optimized for its purpose of application. Frequencies of between 8 and 1000 megahertz (MHz) are preferably transferred with feed-throughs of this type. The high voltage application is also described in U.S. Pat. No. 6,037,539. However, the battery feed-throughs are not described in U.S. Pat. No. 6,037,539.

Lithium-ion accumulators are intended for various applications, for example for portable electronic equipment, cell phones, power tools and in particular electric vehicles. The batteries can replace traditional energy sources, for example lead-acid batteries, nickel-cadmium batteries or nickel-metal hydride batteries. Lithium-ion batteries have been known for many years. In this regard we refer you to the “Handbook of Batteries, published by David Linden, 2nd issue, McGrawhill, 1995, chapters 36 and 39”.

Various aspects of lithium-ion accumulators are described in a multitude of patents, for example: U.S. Pat. No. 961,672; U.S. Pat. No. 5,952,126; U.S. Pat. No. 5,900,183; U.S. Pat. No. 5,874,185; U.S. Pat. No. 5,849,434; U.S. Pat. No. 5,853,914; and U.S. Pat. No. 5,773,959.

In particular in the use of storage devices, such as lithium-ion accumulators in the automobile industry, a multitude of problems such as corrosion resistance, stability in accidents and vibration resistance must be solved. An additional problem is the hermetic seal of the battery, for example the lithium-ion battery over an extended period of time. The hermetic seal may, for example, be compromised by leakage in the area of the electrodes of the battery or respectively the electrode feed-through of the battery. The seal may for example be compromised by a battery short circuit or temperature changes resulting in a shortened life span. An additional problem with battery feed-throughs is the instability against aggressive battery electrolytes, in particular non-aqueous electrolytes as are used, for example in lithium-ion accumulators.

In order to ensure better stability in accidents, a housing for a lithium-ion battery is suggested, for example in DE 101 05 877 A1, whereby the housing includes a metal jacket which is open on both sides and which is being sealed. The power connection is insulated by a synthetic material. A disadvantage of the synthetic material insulation is the limited temperature resistance, the uncertain hermetic seal over the service life and the limited chemical stability in regard to the battery electrolytes.

What is needed in the art is a glass, in particular a solder glass or fusible glass, which avoids the problems of the current state of the art.

SUMMARY OF THE INVENTION

The present invention provides a glass which can be used as a joining glass or fusible glass for a feed-through, for example for a hermetic feed-through, in particular for a storage device with an electrolyte, for example an aggressive electrolyte as used in lithium-ion batteries.

A battery according to the present invention is to be understood to be a disposable battery which is disposed of and/or recycled after its discharge, as well as an accumulator.

As materials for the housing and feed-throughs for lithium-ion accumulators light metal, in particular aluminum, AlSiC, aluminum alloys, magnesium, magnesium alloys, titanium or titanium alloys are feasible.

The inventive glass, in particular solder glass or fusible glass, includes the following components in mole percent (mol-%):

P₂O₅ 35-50 mol-%, for example 39-48 mol-%; Al₂O₃ 0-14 mol-%, for example 2-12 mol-%; B₂O₃ 2-10 mol-%, for example 4-8 mol-%; Na₂O 0-30 mol-%, for example 0-20 mol-%; M₂O 0-20 mol-%, for example 12-19 mol-%;

-   -   whereby M is, for example, potassium (K), cesium (Cs) or         rubidium (Rb);         Li₂O 0-45 mol-%, for example 0-40 mol-%, or 17-40 mol-%;         BaO 0-20 mol-%, or 5-20 mol-%; and         Bi₂O₃ 0-10 mol-%, for example 1-5 mol-%, or 2-5 mol-%.

Additional components are optional and are also included in the present invention. With the exception of contaminants, the glass composition according to the present invention may be lead-free, that is PbO can be 0 mol-% in the glass composition. Lead-free in the current invention means that less than approximately 100 parts per million (ppm), for example less than 10 ppm, or less than 1 ppm lead contaminants are contained therein.

The listed glass compositions are generally stable phosphate glasses which have a clearly lower overall alkali content than alkali-phosphate glasses known from the current state of the art.

Surprisingly it has been shown that the inventive glass composition with a lithium-share of up to 45 mol-%, for example 35 mol-% are crystallization-stable, meaning they do not display detrimental crystallization during a subsequent sintering process. At a lithium-content of up to 35 mol-%, significant crystallization is no longer produced. The high crystallization stability of the phosphate glasses ensures that melting of the glasses generally is not hindered even at temperatures of <600° C. This allows the inventive glass composition to be used as solder glass, since melting of the glasses generally is not hindered even at temperatures of <600° C.

The inventive glass has a heat expansion α in the range of 20° C. to 300° C.>14×10⁻⁶/K and a low soldering temperature or respectively sealing temperature. The soldering temperature or sealing temperature of the glass is surprisingly lower than the melting temperature of the metals aluminum (660° C.), copper (1084° C.), and high-grade steel (>1400° C.). The thermal expansion α (20° C. to 300° C.) is in the range of a (20° C. to 300° C.) of conventional metals such as aluminum (Al) (α≈23×10⁻⁶/K) copper (Cu); (α≈16.5×10⁻⁶/K); and high grade steel (a 17×10⁻⁶/K). The inventive glasses moreover have a high resistance in regard to non-aqueous electrolytes, for example LiPF₆, for example 1 Molar (M) LiPF₆ in ethylene carbonate/dimethyl carbonate 1:1, as well as high hydrolytic resistance to Hydrofluoric acid (HF). The inventive glasses are therefore especially suitable for the production of hermetic feed-throughs for housings for storage cells or storage devices, in particular lithium-ion storage devices.

One advantage of the inventive glass compositions is that lithium is integrated into the glass structure. Since lithium is contained in the electrolyte in the form that the electrolyte is used in lithium-ion storage devices, the battery efficiency should not be impaired. The glass composition moreover has a high heat expansion α in the range of 20° C. to 300° C. and a solder temperature below the melting point of the metals which are to be soldered or sealed, as described above.

Since the diffusion of the alkali-ions occurs in Na+>K+>Cs+ sequence, low sodium or respectively sodium-free glasses are especially resistant to electrolytes, especially those which are used in lithium-ion storage devices.

In a first embodiment of the present invention, the glass composition includes at least 17 mol-% and at most 35 mol-% Li₂O. Such glass compositions are sufficiently resistant in regard to electrodes which contain lithium and also sufficiently crystallization-stable, whereby melting of the glasses is generally not hampered even at temperatures of <600° C.

An additional glass composition according to the present invention includes 4-8 mol-% B₂O₃. Bi₂O₃ in particular can replace the environmentally damaging PbO. Moreover, the addition of Bi₂O₃ can also clearly increase the water resistance. For example, with only a small addition of 1 mol-% Bi₂O₃ an alkali-phosphate glass composition having essentially the same alkali content can be made 10-times more water resistant than an alkali-phosphate composition in which there is no Bi₂O₃ except for contaminants. This effect was surprising for an expert.

Especially preferred for environmental reasons are glasses which—except for contaminants are free of Pb. In this application “free of Pb, except for contaminants” as previously explained means that the glass includes <100 ppm, for example <10 ppm, or <1 ppm lead.

The glass composition, for example, has a coefficient of expansion α (20° C. to 300° C.) in the range of >14×10⁻⁶/K, for example 15×10⁻⁶/K to 25×10⁻⁶/K, or 13×10⁻⁶/K to 20×10⁻⁶/K. Glass compositions with this type of coefficient of expansion or α (20° C. to 300° C.) are adapted to the coefficients of expansion of conventional metals such as aluminum (Al) (α≈23×10⁻⁶/K), Cu (α≈16.5×10⁻⁶/K), and high grade steel (α≈17×10⁻⁶/K). If the glass is to be sealed with light metals like aluminum the glass composition has for example a melting temperature <600° C.

In one embodiment of the present invention, the glass composition has a hemispherical temperature in the range of 500° C. to 650° C., for example in the range of 500° C. to 600° C.

Sealing temperature of the glass or glass ceramic is to be understood to be the temperature of the glass or the glass ceramic whereby the glass material softens and then fits so closely against the metal with which is to be sealed that a bonded joint connection is obtained between the glass or the glass ceramic and the metal.

The sealing temperature may, for example, be determined through the hemispherical temperature as described in R. Girke, K. J. Leers: Keram.Z.48 (1996) 300-305, or according to DIN 51730, ISO 540 or CEN/TS 15404 and 15370-1 whose disclosure content is incorporated in its entirety into the current patent application. The measurement of the hemispherical temperature is described in detail in DE 10 2009 011 182 A1 whose disclosure content is incorporated in its entirety into the current patent application. According to DE 10 2009 011 182A1 the hemispherical temperature can be determined in a microscopic process by using a heating stage microscope. It identifies the temperature at which an originally cylindrical test body melts into a hemispherical mass. A viscosity of approximately log η=4.6 deciPascals (dPas) can be allocated to the hemispherical temperature, as can be learned from appropriate technical literature. If a crystallization-free glass, for example in the form of a glass powder, is melted and then cooled so that it solidifies, it can then normally be melted down again at the same melting temperature. For a bonded connection with a crystallization-free glass this means that the operating temperature to which the bonded connection is continuously subjected may not be higher than the sealing temperature. Glass compositions as utilized in the current application are generally often produced from a glass powder which is melted down and which, under the influence of heat provides the bonded connection with the components which are to be joined. Generally, the sealing temperature or melting temperature is consistent with the level of the so-called hemispherical temperature of the glass. Glasses having low sealing temperatures or respectively melting temperatures are also referred to as solder glass. Instead of sealing or melting temperature, one speaks of solder temperature or soldering temperature in this instance. The sealing temperature or respectively the solder temperature may deviate from the hemispherical temperature by +20K.

According to the present invention, the glass has such a composition that the glass can be soldered or sealed under normal atmosphere with aluminum (Al) and/or copper (Cu). Then, all Al—Al or Al—Cu compositions can be soldered or sealed with the cited glasses. The inventive glasses are especially suited for contact with aggressive fluoric media. These types of fluoric media find application, for example, as electrolytes in lithium-ion batteries.

In accordance with one embodiment of the present invention, the glass or respectively the glass composition has a very high chemical resistance in regard to non-aqueous battery electrolytes, in particular in regard to carbonates, such as carbonate mixtures, for example including LiPF₆.

In addition to the glass or respectively the glass composition, the present invention also cites a feed-through, for example for a storage device, such as a lithium-ion battery, for example a lithium-ion accumulator having an inventive glass composition.

Moreover, a lithium-ion battery with such a feed-through is provided. Even though the current description is for battery feed-throughs, the present invention is not restricted thereto. The glass compositions can be used for feed-throughs of any type, in particular however for those whose base body and/or housing and optionally also the conductor consist of a light metal, such as aluminum. Conceivable feed-throughs are feed-throughs for example for components, in particular electronic components which are used in light construction, for example in aircraft construction in the aerospace industry and which, in particular must have sufficient temperature stability. Electronic components may for example be sensors and/or actuators.

A feed-through, for example for a battery feed-through, in particular for a lithium-ion battery, or for a lithium-ion accumulator has a base body, whereby the base body has at least one opening through which a conductor, for example a substantially pin-shaped conductor embedded in a glass material formed of the inventive composition is guided. The base body contains a material which has a low melting point, for example a light metal, such as aluminum or AlSiC, magnesium or titanium. Alloys, such as light metal alloys, for example aluminum alloys, magnesium alloys or titanium alloys, for example Ti6246 or Ti6242 are also conceivable. Titanium is a material which is well tolerated by the body, so that it is used for medical applications, for example in prosthetics. Due to its strength, resistance and low weight its use is also favored in special applications, for example in racing sports, but also in aviation and aerospace applications.

Additional materials feasible for the base body and/or the battery housing are metals, especially steel, stainless steel, high-grade steel or tool steel which is intended for a later heat treatment. Suitable for use as high-grade steels are for example X12CrMoS17, X5CrNi1810, XCrNiS189, X2CrNi1911, X12CrNi177, X5CrNiMo17-12-2, X6CrNiMoTi17-12-2, X6CrNiTi1810 and X15CrNiSi25-20, X10CrNi1808, X2CrNiMo17-12-2, X6CrNiMoTi17-12-2. In order to be able to provide an especially effective weldability during laser welding as well as during resistance welding, high-grade steels, in particular Cr—Ni-steels (chromium-nickel steels) having material grade numbers according to Euro-Norm (EN) 1.4301, 1.4302, 1.4303, 1.4304, 1.4305, 1.4306, 1.4307 are used as materials for the base body and/or the housing component, in particular the battery cell housing. St35, St37 or St38 can be used as standard steel.

In order to avoid that during the sealing process the light metal of the base body and possibly also of the metal pin melts or deforms, the sealing temperature of the glass material with the material of the base body and/or the conductor is below the melting temperature of the material of the base body or respectively the conductor. The sealing temperature of the cited glass compositions is below 650° C., for example in the range of 350° C. to 650° C. The sealing temperature may for example be determined through the hemispherical temperature as described in R. Girke, K. J. Leers: Keram.Z.48 (1996) 300-305, or according to DIN 51730, ISO 540 or CEN/TS 15404 and 15370-1 whose disclosure content is incorporated in its entirety into the current patent application.

Sealing the conductor into the opening can then be accomplished as follows: First, the glass material of the inventive composition is inserted into the opening in the base body, together with the pin shaped conductor. Then, the glass together with the conductor, in particular the pin shaped conductor, is heated to the sealing temperature or respectively the hemispherical temperature of the glass, so that the glass material softens and envelops the conductor, in particular the pin shaped conductor in the opening and fits closely against the base body. Since the melting temperature of the material of the base body as well as of the conductor, in particular the pin shaped conductor, is higher than the sealing temperature of the glass material, the base body, as well as the pin shaped conductor are in a solid state. The sealing temperature of the glass material is, for example, between 20 to 150 K below the melting temperature of the material of the base body, or respectively of the pin shaped conductor. If for example, the light metal used is aluminum having a melting point of T_(MELT)=660.32° C., then the fusing temperature or respectively solder temperature of the glass material is in the range of 350° C. to 640° C., for example in the range of 350° C. to 550° C., or in the range of 450° C. to 550° C. As an alternative to a light metal such as aluminum, an aluminum alloy, magnesium, a magnesium alloy, titanium, a titanium alloy and an SiC matrix which is infiltrated with aluminum could also be used as material for the base body. A material of this type is also described as AlSiC. AlSiC has a SiC core into which aluminum is infused. Based on the proportion of aluminum the properties, especially the coefficient of expansion can be adjusted. AlSiC notably has a lower heat expansion than pure aluminum.

In the current application metals which have a specific weight of less than 5.0 kilograms per cubic decimeter (kg/dm³) are understood to be light metals. The specific weight of the light metals is, for example in the range of 1.0 kg/dm³ to 3.0 kg/dm³.

If the light metals are additionally used as materials for the conductors, for example for the pin-shaped conductor or the electrode connecting component, then the light metals further distinguish themselves through a specific electric conductivity in the range of 5×10⁶ Siemens per meter (S/m) to 50×10⁶ S/m.

Other feasible materials would be steel, stainless steel or high-grade steel.

The material of the conductor, in particular the pin shaped conductor can be identical to the material of the base body, for example aluminum or AlSiC. This has the advantage that the coefficient of expansion of the base body and the metal pin is identical. The coefficient of expansion at of the glass- or glass ceramic material needs then only to be adapted to one material.

Furthermore, the outer conductor may include high-grade steel or steel.

Alternatively the conductor, in particular the pin shaped conductor may include copper (Cu), CuSiC or a copper alloy, magnesium or magnesium alloys, gold or gold alloys, silver or silver alloys, NiFe, a NiFe jacket with an interior copper part, as well as a cobalt iron alloy as materials.

As aluminum or respectively an aluminum alloy for the conductor, the following are exemplary materials:

-   -   EN AW-1050 A;     -   EN AW-1350;     -   EN AW-2014;     -   EN AW-3003;     -   EN AW-4032;     -   EN AW-5019;     -   EN AW-5056;     -   EN AW-5083;     -   EN AW-5556A;     -   EN AW-6060; and     -   EN AW-6061.

As copper or respectively copper alloys for the conductor, use of the following are exemplary materials:

-   -   Cu-PHC 2.0070;     -   Cu-OF 2.0070;     -   Cu-ETP 2.0065;     -   Cu-HCP 2.0070; and     -   Cu-DHP 2.0090.

In the case that the base body and the metal pin are formed of different materials, α_(base body)≥α_(glass)≥α_(metal pin), for example applies.

If the thermal expansions of the components deviate from each other as previously described, then the result is compression seal feed-throughs or respectively compression seals in the form of special seals, whereby different thermal expansions of glass or glass ceramic material and surrounding metal lead to a frictional connection of glass or glass ceramic material and surrounding metal. These types of compression seal feed-throughs are used for example for airbag igniters. In the case of compression seal feed-throughs the glass or glass ceramic material adheres to the surrounding metal; however no molecular connection exists between the glass or glass ceramic material and the metal. The frictional connection is lost as soon as the opposing force of the static friction is exceeded. A chemical joining of glass or glass ceramic material can be achieved if the surfaces are treated or if the glass material is joined with the surrounding metal through a welding connection, for example an ultrasonic welding connection.

Feed-throughs, in particular battery feed-throughs with the inventive glass composition distinguish themselves in that sealing is possible in a base body consisting of a low melting material and that sufficient resistance is provided in regard to a battery electrolyte. The seal may be a compression seal as well as an adapted seal. In the case of an adapted seal, the coefficients of expansion α (20° C.-300° C.) of glass and surrounding materials or respectively materials to be sealed are essentially the same.

In particular, the glasses have sufficient chemical stability in regard to generally aggressive battery electrolytes. Non-aqueous battery electrolytes consist typically of a carbonate, in particular a carbonate mixture, for example a mixture of ethylene-carbonate and dimethyl-carbonate, whereby the aggressive non-aqueous battery electrolytes have a conducting salt, for example LiPF₆, for example in the form of a 1 Molar (M) solution.

The resistance of the composition according to the present invention against the battery electrolytes can be verified in that the glass composition in the form of a glass powder is ground to a granularity of d50=10 micrometers (μm) and is stored in the electrolytes for a predetermined time period, for example one week. d50 means that 50% of all particles or granules of the glass powder are smaller than or equivalent to a diameter of 10 μm. As a non-aqueous electrolyte, a carbonate mixture of ethylene-carbonate and dimethyl-carbonate is used for example at a ratio of 1:1 with a Molar LiPF₆ as conducting salt. After the glass powder was exposed to the electrolyte, the glass powder can be filtered off and the electrolyte be examined for glass elements which were leached from the glass. Herein it was demonstrated that with the glasses used according to the present invention such leaching in the utilized composition ranges occurs surprisingly only to a limited extent of less than 20 mass percent; and that in special instances leaching of <5 mass percent is achieved at a thermal expansion at in a temperature range of (20° C. to 300° C.) in a range between 15×10⁻⁶/K and 25×10⁻⁶/K. An additional advantage of the glass composition according to the present invention which finds use in a battery feed-through with one or several pins can be seen in that sealing of the glass with the surrounding light metal or respectively the metal of the conductor, in particular in the embodiment of a metal pin is possible also in a gaseous atmosphere which is not an inert gas atmosphere. In contrast to the previously used method, a vacuum is also no longer necessary for aluminum-sealing. This type of sealing can rather occur under atmospheric conditions. For both types of sealing nitrogen (N₂) or argon (Ar) can be used as inert gas. As a pre-treatment for sealing, the metal is cleaned and/or etched, and if necessary is subjected to targeted oxidizing or coating. During the process temperatures of between 300 and 600° C. are used at heating rates of 0.1 to 30 degrees Kelvin per minute (K/min) and dwell times of 1 to 60 minutes.

The inventive glass compositions surprisingly show a high chemical stability relative to the non-aqueous electrolyte and at the same time a high thermal coefficient of expansion. This is surprising especially because it is assumed that the glass becomes increasingly unstable the higher the thermal coefficient. It is therefore surprising that in spite of the high coefficient of expansion and the low sealing temperature the inventive glass compositions offer a sufficient stability.

The listed inventive glass composition can be provided with fillers for the purpose of expansion adaptation that is, for adaptation of the coefficient of expansion.

In order to make the glass composition accessible for infrared-heating or IR-heating, the aforementioned glasses can be provided with doping agents having an emission maximum in the range of infrared radiation, in particular IR-radiation of an IR-source. Examples of materials for this are iron (Fe), chromium (Cr), manganese (Mn), cobalt (Co), vanadium (V), and pigments. The thus prepared glass material can be heated by locally targeted infrared radiation.

The feed-through, in particular a battery feed-through with the inventive glasses in contrast to feed-throughs from the current state of the art, in particular those using plastic as sealing material, moreover distinguishes itself through a high temperature resistance, in particular temperature change resistance. Moreover, a hermetic seal is also provided during temperature change, thus avoiding that battery liquid can emerge from and/or moisture can penetrate into the housing. It is understood that with a hermetic seal the helium leakage rate is <1×10⁻⁸ millibar·Liters per second (mbar·L/s), for example <1×10⁻⁹ mbar·L/s at a pressure differential of 1 bar.

The feed-through according to the present invention, in particular the battery feed-through, has a sufficient chemical stability, in particular in regard to non-aqueous battery electrolytes.

The feed-throughs can be used with the inventive glass compositions or glasses in electrical devices, in particular in storage devices, in particular a battery, preferably a battery cell. The housing of the battery cell consists, for example of the same material as the base body of the feed-through, such as a light metal. In the case of battery cells, the base body is, for example part of the battery housing. The battery is, for example, a lithium-ion battery.

The battery may have a non-aqueous electrolyte, for example on a carbonate basis, such as a carbonate mixture. The carbonate mixture can include ethylene-carbonate mixed with dimethyl-carbonate with a conducting salt, for example LiPF₆.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawing, wherein:

FIG. 1 illustrates an inventive feed-through.

The exemplification set out herein illustrates one embodiment of the invention and such exemplification is not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawing, and more particularly to FIG. 1, there is shown a feed-through 1 according to the present invention. Feed-through 1 includes a metal pin 3 as a conductor, in particular as a pin shaped conductor which consists for example of a material, such as aluminum or copper. It further includes a base body 5 in the embodiment of a metal part consisting according to the present invention of a metal which has a low melting point, that is a light metal such as aluminum. Metal pin 3 is guided through an opening 7 which leads through metal part 5. Even though only the insertion of a single metal pin through the opening is illustrated, several metal pins could be inserted through the opening, without deviating from the present invention.

The outer contour of opening 7 can be round, but also oval. Opening 7 penetrates through the entire thickness D of base body 5, or respectively metal part 5. Metal pin 3 is sealed into a glass material 10 and is inserted inside glass material 10 through opening 7 through base body 5. Opening 7 is introduced into base body 5 through a separation process, for example stamping. In order to provide a hermetic feed-through of metal pin 3 through opening 7, metal pin 3 is sealed into a glass plug consisting of the inventive glass material. A substantial advantage of this production method consists in that even under increased pressure upon the glass plug, for example a compression load, expulsion of the glass plug with metal pin from opening 7 is avoided. The sealing temperature of inventive glass material 10 with the base body 5 is 20K to 100K below the melting temperature of the material of base body 5 and/or of the conductor 3, for example the pin shaped conductor 3.

TABLE 1 Examples (AB1-AB8): Mol-% AB1 AB2 AB3 AB4 AB5 AB6 AB7 AB8 P₂O₅ 47.6 43.3 43.3 43.3 37.1 40.0 42.0 46.5 Al₂O₃ 4.2 8.6 8.7 2.0 2 12.0 12.0 4.2 B₂O₃ 7.6 4.8 4.7 4.8 4.9 6.0 6.0 7.6 Na₂O 28.3 17.3 15.0 16.0 28.3 K₂O 12.4 17.3 17.3 18.0 19.0 12.4 PbO 9.0 0 0 BaO 8.7 8.7 15.4 14 Li₂O 17.3 34.6 42.1 Bi₂O₃ 5 1 Hemispherical 513 554 564 540 625 553 502 Temperature (° C.) α (20-300° C.) 19 17.2 15.1 13.7 14.8 16.7 16.0 19.8 (10⁻⁶/K) Tg (° C.) 325 375 354 369 359 392 425 347 Density 2.56 3 3 [g/cm³] Leaching in 18.7 3.7 3.7 Mass % Weight 10.7 0.37 0.1 0.13 0.13 n.b. 0.006/0.001 0.45/0.66 Loss (%) after 70 hours in 70° C.- water

Besides leaching, the hydrolytic resistances of the individual glasses were also determined.

The hydrolytic resistance tests were conducted so that melted down glass samples were produced (2×2 centimeters (cm), height: ˜0.5 cm) which were stored in 200 milliliters (ml) water at 25° C. and 70° C. for 70 hours. Subsequently the material loss in weight-% was determined and listed in the table.

Example 1 (AB1) in Table 1 is suitable, for example, for aluminum/aluminum sealing, that is sealing an aluminum pin as conductor into a surrounding aluminum base body.

Even though some of the examples indicate a coefficient of expansion which is too low for bonding with copper (Cu) it becomes clear that a high lithium component can be dissolved in the molten mass without the glass becoming unstable with a glass composition of this type.

Examples AB7 and AB8 distinguish themselves in that they contain Bi₂O₃, in place of PbO, as is the case in example 6 (AB6).

Surprisingly it has been shown that the hydrolytic resistance can be clearly increased by including Bi₂O₃. For example, by introducing 1 mol-% Bi₂O₃, a 10-times higher hydrolytic resistance can be achieved compared to example AB1. Bi₂O₃, can in particular also be used in place of PbO according to example 6. Exemplary glass compositions according to the present invention which distinguish themselves as being environmentally friendly are lead free, in other words free of PbO, except for contaminants. These are for example examples AB1, AB2, AB3, AB4, AB5, AB7 and AB8.

An especially crystallization stable glass composition which displays no, or almost no substantial crystallization is achieved when the lithium content is less than 35 mol-%, for example less than 20 mol-%. These are for example examples AB1, AB2, AB3, AB4, AB6, AB7 and AB8.

A special resistance in regard to electrolytes is achieved if the sodium content is less than 20 mol-%. This is especially true of sodium free glasses, in other words glasses which are free of sodium except for contaminants. These are for example the examples AB2, AB3, AB4, AB5, AB6 and AB7.

An especially high hydrolytic water resistance is achieved, if at least 1 mol-% Bi₂O₃, for example at least 2 mol-% Bi₂O₃ is present in the glass composition. This is the case for example in examples AB7 and AB8.

Table 2 below lists conventional glass compositions (VB1-VB9) which were examined in comparison to the aforementioned inventive examples AB1-AB8.

Tables 1 and 2 show the composition in mol-%, the transformation temperature Tg as defined for example in “Schott Guide to Glass, second edition, 1996, Chapman & Hall, pages 18-21, the total leaching in mass percentage (Ma-%), the coefficient of expansion at in 10⁻⁶/K in the range of 20° C.-300° C., as well as the density in grams per cubic centimeter (g/cm³). The total leaching is determined as described in the introductory section, meaning that the glass compositions were ground to glass powder having a d50=10 micrometers (m) granularity, and were exposed for one week to the electrolyte consisting of ethylene-carbonate/dimethyl-carbonate at a ratio 1:1, with 1 Molar LiPF₆ in the form of conducting salt dissolved therein and after this time were examined for glass components which were leached from the glass. “n.b.” in Table 1 denotes unknown properties.

TABLE 2 Comparison examples VB 1 VB 2 VB 3 VB 4 VB 5 VB 6 VB 7 VB 8 VB 9 Composition System [mol-%] SiO₂ SiO₂ SiO₂ SiO₂ P₂O₅ P₂O₅ P₂O₅ P₂O₅ P₂O₅ SiO₂ 66.5 66.6 63.3 77.8 55.4 2.6 ZrO₂ 2.4 11.8 Al₂O₃ 9.3 10.4 1.0 3.3 8.4 5.5 12.8 4.0 7.4 B₂O₃ 4.0 7.3 4.1 9.4 31.2 1.7 MgO 4.0 4.4 3.3 4.3 20.5 2.9 BaO 3.8 1.5 2.5 0.2 7.0 7.8 La₂O₃ 1.3 Li₂O 0.6 K₂O 7.9 2.0 2.4 P₂O₅ 5.3 6.8 29.3 59.7 50.5 CaO 12.3 9.6 4.7 1.6 7.9 8.1 Na₂O 9.1 7.0 0.5 SrO 11.3 F 1.0 0.6 54.7 PbO SnO 27.0 42.2 ZnO 8.9 Tg 720 716 508 562 464 680 n.b. 462 n.b. Total leaching in Mass % 43.5 52.4 167.0 64.4 2.1 127.6 50.2 18.8 1.9 α (20° C.-300° C.) 4.6 3.8 10.4 4.9 14.8 5.5 n.b. n.b. n.b. Density [g/cm³] 2.6 2.5 n.b. 2.3 3.7 2.8 n.b. 2.8 n.b. The comparison examples VB1, VB2 and VB6 cited in table 2 show a transformation temperature Tg which is too high and a thermal coefficient of expansion α which is too low compared to the inventive compositions (AB1-AB8) in table 1. Comparison example VB3 does have a sufficiently low Tg, a better, however not sufficient coefficient of expansion α (20° C. to 300° C.), however a high instability in respect to electrolytes. Comparison example VB4 shows a favorable Tg, however the resistance and the coefficient of expansion α are not sufficient. Comparison example shows VB5 an excellent resistance, the Tg is satisfactory, however the coefficient of expansion α is not sufficient.

Surprisingly, inventive examples AB1 to AB8 of the inventive glass compositions according to table 1 show a high a, (20° C.-300° C.) according to the present invention, low Tg and high chemical resistance. The inventive glass compositions thereby provide sealing glasses for use in battery feed-throughs, having a low process temperature, a sealing temperature which is lower than the melting point of aluminum, a high coefficient of expansion α and an excellent resistance to battery electrolytes. Even though the glass compositions are described for use in feed-throughs, in particular battery feed-throughs they are not restricted thereto. Other fields of application are, for example, sealing of housings, of sensors and/or actuators. In principle the feed-throughs are suitable for all applications in lightweight construction, in particular as feed-throughs in electrical components which must be light and temperature resistant. Such components are found for example in aircraft construction and in astronautics.

While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. 

What is claimed is:
 1. A feed-through, comprising: a glass having a composition including in mole percent (mol-%): P₂O₅ 35-50 mol-%; Al₂O₃ 0-14 mol-%; B₂O₃ 2-10 mol-%; Na₂O 0-30 mol-%; M₂O 0-20 mol-%, wherein M is one of potassium, cesium and rubidium; Li₂O 0-42 mol-%; BaO 0-20 mol-%; and Bi₂O₃ 1-10 mol-%.
 2. The feed-through according to claim 1, the glass having a composition including: P₂O₅ 39-48 mol-%; Al₂O₃ 2-12 mol-%; B₂O₃ 4-8 mol-%; Na₂O 0-20 mol-%; M₂O 12-19 mol-%; Li₂O 0-40 mol-%; BaO 5-20 mol-%; and Bi₂O₃ 1-5 mol-%.
 3. The feed-through according to claim 2, the glass composition including: Li₂O 17-40 mol-%; and Bi₂O₃ 2-5 mol-%.
 4. The feed-through according to claim 1, wherein the glass is a solder glass.
 5. The feed-through according to claim 1, the glass including at most 35 mol-% Li₂O.
 6. The feed-through according to claim 1, the glass including at least 17 mol-% Li₂O.
 7. The feed-through according to claim 1, the glass including 4-8 mol-% Bi₂O₃.
 8. The feed-through according to claim 1, the glass being lead free except for contaminants.
 9. The feed-through according to claim 1, the glass including at most 20 mol-% Na₂O.
 10. The feed-through according to claim 1, the glass including at least 2 mol-% Bi₂O₃.
 11. The feed-through according to claim 1, the glass having a coefficient of expansion α at a temperature in a range of between 20° C. and 300° C. of >14×10⁻⁶ per degree Kelvin (K).
 12. The feed-through according to claim 11, the glass having a coefficient of expansion α at a temperature in a range of between 20° C. and 200° C. being in a range of between 13×10⁻⁶/K and 20×10⁻⁶/K.
 13. The feed-through according to claim 11, said coefficient of expansion α at said temperature in said range of between 20° C. and 300° C. being in a range of between 15×10⁻⁶/K and 25×10⁻⁶/K.
 14. The feed-through according to claim 1, the glass having a melting temperature of <600° C.
 15. The feed-through according to claim 1, the glass having a hemispherical temperature in a range of between 500° C. and 650° C.
 16. The feed-through according to claim 1, the glass having a composition such that the glass can be soldered at normal atmosphere with at least one of aluminum and copper.
 17. The feed-through according to claim 1, the glass having a high chemical resistance to electrolytes, the electrolytes being at least one selected from the group consisting of non-aqueous electrolytes, carbonates, carbonate mixtures and LiPF₆.
 18. The feed-through according to claim 1, the feed-through being for a device.
 19. The feed-through according to claim 18, wherein said device is a storage device.
 20. The feed-through according to claim 19, wherein said storage device is a lithium-ion accumulator.
 21. The feed-through according to claim 20, wherein said lithium-ion accumulator is a lithium-ion battery.
 22. A device, the device comprising: a feed-through including a glass having a composition including in mole percent (mol-%): P₂O₅ 35-50 mol-%; Al₂O₃ 0-14 mol-%; B₂O₃ 2-10 mol-%; Na₂O 0-30 mol-%; M₂O 0-20 mol-%, wherein M is one of potassium, cesium and rubidium; Li₂O 0-42 mol-%; BaO 0-20 mol-%; and Bi₂O₃ 1-10 mol-%.
 23. The device according to claim 22, the device being a storage device.
 24. The device according to claim 23, wherein said storage device is an accumulator.
 25. The device according to claim 24, wherein said storage device is a lithium-ion accumulator.
 26. The device according to claim 25, wherein said lithium-ion accumulator is a lithium-ion battery. 